The present invention relates generally to methods of roof construction, and more particularly relates to an improved method for adhering roof tiles to substrates using economical one-component adhesives, including one-component high-density polyurethane adhesive foams.
Roof construction, especially in residential construction, varies by location throughout the United States. In the northern climates, most roofs utilize a thin covering of tar paper-based shingles or thick wooden shingles as a final covering for the roof. In southern climates, tiles are used as the final covering of the roof. These roof tiles may be made from a variety of materials, including synthetic materials, such as plastics, and natural materials, such as stone, concrete, clay, ceramic and fired brick. In the application of these latter types of roof tiles, mortars or cementitious materials have been used in the past to apply the roof tiles to the roof substrate.
The use of mortars as roof tile adhesives is expensive because the mixing and application of the mortar is very labor intensive. Mortars are dense materials and their use as roof adhesives increases the load placed on the roof. The curing time for mortar may also be relatively long, thereby hampering quick completion of the roof. A need therefore exists for a lighter adhesive which is less labor intensive than mortar and which lends itself to efficient application of roof tiles.
Adhesives, and in particular adhesive foams, have been developed to replace mortars used in roof construction. U.S. Pat. No. 5,362,342, issued Nov. 8, 1994 describes the use of a two-component polyurethane foam to bond roof tiles to a substrate. This patent further describes the use of a bulky, complex pressurized dispensing system which is necessary to mix the two components together so that they may react to create a sufficient amount of foam with the desired adhesive characteristics. The aforesaid '342 patent further describes a particular method of using two-component foams to bond roof tiles to a roof substrate in which thick, linear beads of foam are applied to the entire length of the roof tiles.
One-component adhesives, such as those sold under the trade name INSTA-STIK by Insta-Foam of Joliet, Ill. have been utilized in the past, primarily for adhering roof insulation boards to roof substrates. These one-component adhesives are collapsible foams and are applied in long beads of foam for all or most of the entire length of the insulation boards to adhere the insulation boards to the roof. The use of long, linear beads of adhesives increases the cost of applications by using large amounts of adhesives and lengthening the application process.
The present invention is directed to a roof tile adhesion method which uses inexpensive one-component adhesives, and in a preferred embodiment one-component polyurethane adhesive foams, in a novel application pattern which significantly reduces the amount of adhesive used per roof tile without detracting from its adhesive strength.
It is therefore an object of the present invention to provide a method of adhering roof tiles to a roof substrate using economical one-component adhesives, including one-component adhesive foams.
Another object of the present invention is to provide a method for adhering roof tiles to a substrate using a modest amount of adhesive in a unique pattern which reduces the amount of adhesive used for application, yet provides sufficient adhesive strength between the roof tile and the substrate.
Yet another object of the present invention is to provide a method for adhering roof tiles to a substrate by applying a one-component, high-density polyurethane adhesive foam to opposing corners of the roof tile and placing the tiles into contact with the substrate, and letting the adhesive foam cure to adhere the roof tile to the substrate.
Still yet another object of the present invention is to provide an improved tiled roof construction having a substrate, a plurality of roof tiles adhered to the substrate, the roof tiles being adhered to the substrate by an adhesive deposited in alignment with opposing corners of the roof tiles, the adhesive deposits having a pad-like profile, the adhesive pads adhering opposite corners of the tile to the roof substrate and a preceding tile course, the adhesive pads further defining a discontinuous adhesive pattern which does not subdivide the space between the tile undersurfaces and the roof substrate into discrete spaces to restrict air circulation between the roof tile and the roof substrate.